Measuring the forces which are applied to a crank during a cycling motion is well known. Several methods have been developed to correlate the amount of force and/or torque applied to a crank with its angular position in order for example to assist an athlete in optimising his/her cycling action. An XY hall-effect magnetic sensor and donut magnet have been used to assist in the determination of a crank's angular position. This kind of prior art method requires a complex set up and relatively complex components on both the crank and the frame.
One of the objectives of the invention is to simplify the method of measuring a cycle crank angular position. Another object of the invention in certain aspects is to increase the accuracy of the method. Another object of the invention in certain embodiments is to provide for a system which can be housed within the crank itself and substantially reduce the components which might be external to the crank.